PROJECT SUMMARY Chronic Obstructive Pulmonary Disease (COPD) is a healthcare epidemic that disproportionately impacts patients in rural communities. Disparities in COPD-related morbidity and mortality are especially prominent in South Central Appalachia, which represents one of the most disadvantaged regions in the United States. Regional differences in household air pollution (HAP) exposure may contribute to inequality in COPD related morbidity, though research on the contribution of indoor air to this disparity is lacking. As US adults spend roughly 85% of their time in indoor environments, this represents a critical research gap. In-home heating practices, specifically use of solid fuels (i.e. coal and wood), represent a uniquely rural source of HAP that may be more detrimental to COPD morbidity than urban sources of pollution. Combustion of solid fuels releases elevated concentrations of small-diameter particulate matter (PM). The particles can penetrate deep into the lung (fine PM) and even translocate into the bloodstream (ultrafine particles, UFP) Preliminary work by our group suggests that indoor burning of solids fuels is prevalent in rural communities, and that homes in Appalachia using solid fuels have indoor PM concentrations exceeding the concentrations typical of urban settings. We hypothesize that household air pollution created by use of solid fuels for heating in rural communities is associated with worsened respiratory morbidity for patients with COPD. To study the link between heating practices, particulate matter, and respiratory morbidity in rural COPD, on both nationwide and local level we will utilize two complementary sources: (1) A nationally representative dataset - the National Health and Nutrition Examination Survey (NHANES) ? linked to US Census and American Community Survey data (2) A cohort of former smokers with COPD living in central Appalachia evaluated as part of the CURE COPD study; a cohort undergoing comprehensive environmental and clinical monitoring. Two novel aims are proposed: (1) To investigate the association between solid fuel use and rural COPD morbidity in a nationally representative study. A unique dataset is being constructed linking NHANES to the US Census /American Community Survey data that will provide information on household heating practices, urban/rural residency, and respiratory morbidity. (2) To investigate the association between heating practices, UFP exposure, and COPD morbidity among a cohort participants (n=40) with COPD in the central Appalachia cohort. Continuous weeklong monitoring of UFP and fine PM will be added to the parent protocol. We will also add daily monitoring of lung function and respiratory symptoms, to link household PM measurements to daily respiratory symptoms. This two-population approach will allow us to identify effects of solid fuel heating, on rural COPD morbidity in both a large US dataset and a smaller cohort of high-risk individuals living in Appalachia. Study results will inform the need for and design of interventions aimed at reducing HAP in rural regions and improving COPD related outcomes.